A gray cap with white patches and a radially grooved margin, and a stalk with a large, white, saclike cup around the base. June–September. Cap oval, becoming bell-shaped to convex or flat, with a central knob; gray, occasionally with a few white patches; texture smooth, tacky when wet; margin radially grooved. Gills: width moderately broad; spacing close to crowded; whitish; attachment free. Stalk cylindrical, with an elongated, white, saclike cup around the base; whitish; texture smooth or mealy; hollow, lacking a ring. Universal veil white, sometimes leaving patches on the cap and a large, white, saclike cup around the base of the stalk. Spore print white. Spores magnified are round, smooth.
Lookalikes: Other Amanita species.